when the economy imploded, john mccain's advisors say his campaign collapsed along with it and never recovered. historians say in order for an october surprise to have a real 11th hour impact, it has to feed into a narrative that already exists, whether it's carter's ineffectiveness or questions about mccain's credentials on the economy. >> it's not so much that suddenly eureka, this is so surprising, so amazing, but rather, people nod yes, this is where we thought things were going. >> reporter: it's possible we may have already seen this election year's october surprise. maybe it was how the candidates reacted to tragedy in libya and the broader unrest in the mideast or maybe it was mitt romney's now infamous 47% remarks, or perhaps one or both of the campaigns is holding damaging information about the other, or there will be an unforeseen event on the world stage. it's hard to say, since if we could guess, it would not be called an october surprise. dana bash, cn washington. >> we shall see what happens. >>> he was by far -- he was by the side of the iranian president during his v